Collapsible tubing with protective rib



w. E. REJEsKl 2,841,183

July 1, 1958 COLLAPSIBLE TUBING WITH PROTECTIVE RIB Filed June 9, 1955 L A "een IN V EN TOR.

United States Patent 2,841,183 I A t coLLAPsIIBLE TUBlNG'WITH PROTECTIVE RiB William E. Rejeski, Farmington, Conn., assignor to The Wiremold Company, West Hartford, Conn., a corporation ofConnecticut A Application June 9, 1955, serial Nq. 514,2.,85

14 claims. (ci. 1387.60)

This inventionV relates to rimprovements in. Collapsible tubing formed of a convoluted metal strip, the adjacent convolutions of which are connected by .fabric or mother flexible material in theform'of a strip which may'be comprised of one or more laminations whose edges are frictionally held by the folded-over edges of the metal strip. More particularly, the invention relates to the provision of a scuri rib in such tubing; V

Collapsible tubing made of two or moreY elements has heretofore been made including various structuralinl--V provements to improve the ilow of air or gas and to protect the flexible strip from wear and scuffng, particularly where it is joined to the metal strip. While some of these prior structures have gone into use and been satisfactory undersome conditions, there are conditions of use which require greater protection of the flexible strip and a smoother interior surface to improve the flow and also -to avoid being caught on sharp objects. Also, the prior structures which aimed to satisfy `the foregoing conditions were not well adapted to laminated flexible strips since laminations, when folded, tend undesirably to i11- crease in bulk at the fold and make it difficult, if not impossible, to fabricate a satisfactory joint with a metal strip.

Therefore, one object of the invention is to provide an improved collapsible tubing construction in which a laminated flexible strip can be used to join adjacent convolutions of a metal strip whose edges frictionally hold the flexible strip.

Another object is to provide an improved collapsible tubing construction having a scuff rib on the metal strip outside the tubing to protect the tubing and in a position where it can be controlled.

Another object is to provide an improved collapsible tubing construction of the foregoing type in which the interior is smoother, providing for freer ilow of gas than heretofore.

Other objects and advantages of the invention will appear as it is described in connection with the accompanying drawing.

In the drawing:

Fig. 1 is a fragmentary longitudinal section view of two convolutions of collapsible tubing embodying the invention.

Fig. 2 is a view similar to Fig. 1 but of another form of the invention.

Fig. 3 is a view similar to Fig. 1 but of a third form of the invention.

Fig. 4 is a view similar to Fig. 1 of a fourth form of the invention.

Referring to the drawing, the tubing comprises a helically wound spring wire over and around which a strip of metal is folded on its longitudinal center line. Preferably, the interior surfaces of the portions 12 and 14 of the trailing and forward portions, respectively, of the strip, now lying on opposite sides of the wire 10, are bent into engagement inside the Wire helix. Both por- Y 2,841,183 Patented July 1,

ice

tions -12 and 14 are continued radially inward a short distance, and then bent oppositely parallel to the axis of the tubing, as at 16 and 18. The trailing and forward edges 24, 26`of the metal strip are reversely bent outwardly and folded down over the outer surfaces of the axially-directed portions 16, 18 respectively.

The flexible component of the tubing (as distinguished from the helical spring wire 10 and the metal strip both of'which are resilient in different degrees, but not flexible or pliable like a piece of cloth or thin plastic sheeting) may comprise a ilexible strip of cloth, fabric, synthetic plastic sheeting or other limp exible material, i. e., lacking stiffness. The strip may have one, two or more layers or laminations. The laminations may be of the same or different materials to satisfy different conditions insideand outside the tubing. For example, but not by way of limitation, the inner lamination 30 may have to resistA temperatures well above room temperature while the outer lamination 40 may have to withstand wear and rough handling. Also, a third lamination 50 such.

as of insulation is sometimes necessary between the inner and outer layers as shown in Fig. 4, in which like nu- Itrals represent like parts of Fig. 1. Hence, when referring to the flexible strip, it will be understood that a Single or multiple laminated strip is contemplated, without specific limitation as to the number of layers.

Prior to folding down the metal strip edges 24, 26 all the way, the trailing edge 32, 42 of the flexible strip is turned under, and the turned-under edge is inserted under the'forward edge 26 of one convolution of the metal Strip; andthe forward edge 31, 41 of the flexible strip is similarly turned under and is inserted under the trailing edge 24 of the adjacent convolution of the metal strip. Thereafter, the folded edges 24, 26 of the metal strip are bent down tightly on the inserted flexible strip edges 31, 32 to frictionally hold them and all laminations thereof with a rm and permanent grip.

By pressing the edges 24 and 26 toward the periphery, the metal strip where the latter surrounds the wire, or vice versa, the flexible strip can be pinched therebetween to provide additional holding of the elements.

The spring 10 expands the tubing when not stored or under compression for other reasons. Although this spring is desirable in some instances, such as in large diameter tubing, it may not be necessary in all cases and may be omitted, if desired. The metal strip, being formed in a helix, suffices in such cases to expand the tubing; or the tubing may be pulled to full length.

In the form of the invention of Fig. 2, the spring wire has been omitted but the metal strip is laterally bent circularly along its longitudinal central axis as in the previous form. Instead of being bent radially inward after touching, the trailing and forward portions 112, 114 are reversely bent a short distance and then bent parallel to the axis of the tubing, but in opposite directions as at 116, 118. Then, their longitudinal edges 124, 126 are bent reversely inwardly in position to grip between themselves and the portions 116, 118 respectively, the longitudinal edges 132, 142 and 131, 141 of the flexible strips to frictionally hold the same when the reversely bent edges are pressed toward the portions 116, 118.

In the form of the invention of Fig. 3, one half (shown only for example as the left half) of the metal strip-as viewed in cross section and on either sides of the radial median line of itself and of the tubing--is formed as in the form of Fig. 1, while the other (right half) is formed as in the form of Fig. 2. Alternatively, the right half could be as in Fig. 3 and the left half as in Fig. l. In Fig. 3, similar reference numerals are used to those of Figs. l and 2 but with a prime added.

It will be clear that in each of the possible forms, a scuff rib is formed by the bending of the metal strip; and

:that rib will protect the outside of the exible of the i .i I

tubing from abrasion, wear and tear. Also, in each form,

the spring wire can be used as conditions indicate the need, or dispensed with.when not necessary.v Further, each form is adapted to permitv the use of arpluralit'y of plies, layers or .laminations ofthe flexible stripwithout the 'joint of the flexible strip with the metal strip becoming to'o bulky.

In each of the forms, the protrusion of the metal can i 5. Collapsible tubing as claimed in claim 1 having a spring wire within the rib tending to expandl the tubing. 6. Collapsible tubing as claimed in claim 1 in which the reverse bend of at least one edge of the metal strip is outward and a portion of the flexible strip lies upon the outside of said reversely bent edge.

7. Collapsible tubingv as claimed in claim 6 in which the rib is tubular in cross section. 8. Collapsible tubing as claimed in claim 7 having a spring wire within the rib tending to expand the tubing.

9. Collapsible tubing as claimed in claim 7 in which the exible tubing is laminated and in which said n'b bears against said exible tubing pressing it against the reversely bent edge of the metal strip.

10. Collapsible tubing as claimed in' claim 1 in which the flexible tubing is laminated.

l1. Collapsible tubing as claimed in claim 1 in which therib is tubular in cross section, said rib bearing against ly bent, a liexible strip having an edge inserted between 2. Collapsible tubing as claimed in claimv l in which the flexible tubing is laminated, one lamination being capable of resisting temperatures above room temperature, another lamination being wear-resistant.

3. Collapsible tubing as claimed in claim 2 having an intermediate third lamination of insulating material.

,4. Collapsible tubing as claimed in claim 1 in which the rib is tubular in cross section.

said exible tubing and pressing it against the reversely bent edge ofthe metal strip.

12. Collapsible tubing as claimed in 'claim 1 in which the reverse bend of at least one of the edges of the metal strip', is inward.

13. Collapsible tubing' as claimed in claim 12 in which the rib is tubular in cross section.

14. Collapsible tubing as claimed in claim 1 in which one edge of the metal strip is reversely bent outwardly and theother edge is reversely bent inwardly.

References Cited in the le of this patent UNITED STATES PATENTS 

